Plasma reaction, apparatus for decreasing nox by occlusion catalyst using the same

ABSTRACT

A plasma reaction apparatus and method applied to reformation of fuel by generating and using rotating arc plasma in a furnace, the chemical treatment of a persistent gas, and the apparatus for decreasing NOx by an occlusion catalyst. A raw material for a reaction is allowed to flow into the furnace through a hole, causing it to flow within the furnace in a continuous swirl. Furthermore, an expanded plasma reaction zone is provided by a wide area chamber which is formed on an upper part of the furnace and has a greater width than that of a lower part of the furnace, and thus a plasma being generated can be expanded by the expanded plasma zone and delayed from flowing out of the furnace by corners of the wide area chamber that is spaced from a plasma inducing electrode therein.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 11/992,077, filed Sep. 11, 2009, the disclosure ofwhich is incorporated herein by reference in its entirety. Thisapplication claims priority benefits under 35 U.S.C. §1.119 to KoreanPatent Application No. 10-2006-0072722 filed Aug. 1, 2006, 1 0-2006-002181 8 filed Mar. 8, 2006, 10-2005-0111486 filed Nov. 21, 2005, and10-2005-0094929 filed Oct. 10, 2005, the disclosures of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a plasma reaction apparatus and aplasma reaction method using the same, and more particularly, to aplasma reaction apparatus which generates rotating arc plasma and whichis applied to the reforming of fuel and the chemical treatment ofpersistent gas, using the rotating arc plasma, and a plasma reactionmethod using the same.

BACKGROUND ART

In general, states of matters are divided into three states, i.e., asolid, a liquefied and a gas. When energy is applied to a solid, thesold becomes a liquefied, and when the energy is further applied to theliquefied, the liquefied becomes a gas. When the higher energy isapplied to the gas, there is generated plasma in a fourth state ofmatter which consists of electrons and ions having electric polarity. Innature, plasma is observed in the form of lightening, an aurora, and anion layer in the air. In daily life, artificially produced plasma isincluded in a fluorescent lamp, a mercury lamp and a neon sign.

When a gas with high kinetic energy is collided at ultra hightemperature, electrons with negative electric charges are dissociatedfrom atoms or molecules, thereby making the plasma. The plasma means thegaseous state which is divided into the electrons with negative electriccharges and the ions with positive electric charges. Plasma has thedegree of ionization of the electric charges which is significantlyhigh. Plasma generally contains the negative electric charges and thepositive electric charges in about equal numbers, so that the electriccharges are distributed in about equal density. Therefore, plasma isalmost in an electrically neutral state.

The plasma is classified as high temperature plasma and low temperatureplasma. The high temperature plasma has high temperature like an arc.The low temperature plasma has nearly normally room temperature becausethe energy of the ions is low whereas the energy of the electrons ishigh. The plasma is generated by applying the electrical methods, suchas direct current, super-high frequency and electron beam, and ismaintained by using the magnetic field.

A plasma generating technique and plasma practical use considerably varydepending on the pressure condition at which the plasma is generated.Since the plasma is stably generated on the vacuum condition with lowpressure, the plasma generated in this manner is used for chemicalreaction, deposition and corrosion in a semiconductor device fabricationprocess and a new material composition process. The plasma generated onthe air pressure condition is used for processing a harmful gas toenvironment or manufacturing a new matter.

A plasma reaction apparatus for using the plasma needs to have theoperability to start a reaction promptly, the high durability, and theefficiency on reaction. Upon the plasma reaction, the forms of anelectrode and a furnace and the conditions for reaction (for example, avoltage and an additive) are decisive factors for the plasma reaction.Accordingly, a desirable constitution of the plasma reaction apparatusneeds to be presented to correspond with the required performance, and atechnique of a plasma reaction method needs to be presented for theoptimization of the reaction conditions.

DISCLOSURE Technical Problem Technical Solution

The present invention provides a plasma reaction apparatus which enablesa raw material to be sufficiently reacted within a plasma reaction spacehaving a restrictive volume and enables a high plasma reaction to befaster performed, and a plasma reaction method using the same, andvarious plasma apparatuses relating to the plasma reaction apparatus andthe plasma reaction method using the same, in which a plasma reactionzone is expanded to temporarily stay before it is discharged, therebyexcluding the discontinuity of the plasma reaction zone.

The present invention also provides, as an application field, a plasmareaction method of a persistent gas, which effectively resolves apersistent gas by maintaining a plasma region, which is formed inside afurnace, at higher temperature, increasing an average collision path ofelectrons, and generating radicals and ions with high reactivity.

The present invention also provides, as another application field, aplasma reactor which independently supplies a reducing ambient gas ofhigh temperature, which does not interfere an operation of an engine,and which promptly supplies the ambient gas by a prompt reaction whichis the characteristic of a plasma reforming reaction when needed, and anapparatus for decreasing NOx by an occlusion catalyst, using the plasmareactor.

The present invention also provides a plasma reactor which realizes thesimplification of the constitution by receiving fuel from a storage forsupplying the fuel to an engine so that is realized and whichinsignificantly improves the reforming performance of the fuel byeffectively mixing the liquefied fuel and gas being supplied to theplasma reactor, and an apparatus for decreasing NOx by an occlusioncatalyst, using the same.

Advantageous Effects

As described above, when persistent gas, hydrocarbon fuel and anoxidizer as partial oxidation conditions are flowed into the inside of afurnace and a plasma region is maintained at higher temperature by heatgenerated by the oxidation reaction of the fuel, an average collisionpath of electrons is increased and radicals and ions with highreactivity in the oxidation reaction are generated, thereby effectivelyresolving the persistent gas.

Furthermore, a plasma reaction zone generated upon a plasma reaction isstayed by an expansion section formed in a furnace and by a tip partformed upon the expansion, thereby realizing a continuous plasmareaction.

Furthermore, a raw material is flowed into an intake hole having a swirlstructure and the raw material progresses in a rotating flow, therebyenabling the raw material to be sufficiently reacted in a plasmareaction space with a restrictive volume and enabling a faster hightemperature plasma reaction to be formed.

Furthermore, prior to discharge, a plasma reaction zone is expandedthrough a broad area chamber formed as an upper width of a furnace isexpanded, and the plasma reaction zone is temporarily stayed, therebyremoving discontinuity of the plasma reaction zone.

Consequently, the above-described effects achieve the objects of thepresent invention to improve the reaction efficiency upon the reformingreaction of raw materials being supplied or upon the process of harmfulmatters and to enhance the reliability of resultant products and to beadvantageous to environment.

DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical sectional view illustrating a plasma reactionapparatus according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view illustrating a plasma reaction zonewhich is expanded by the plasma reaction apparatus of FIG. 1.

FIG. 3 is a cross sectional view illustrating a structure in which a rawmaterial inflow pipe is operatively connected to a furnace in the plasmareaction apparatus of FIG. 1.

FIG. 4 is a vertical sectional view illustrating a plasma reactionapparatus according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view illustrating a plasma reaction zonewhich is stayed by the plasma reaction apparatus of FIG. 4.

FIG. 6 is a cross sectional view illustrating the plasma reactionapparatus of FIG. 4.

FIG. 7 is a vertical section view illustrating a plasma reactionapparatus according to a third embodiment of the present invention.

FIG. 8 is a cross sectional view illustrating a structure in which aninflow path is formed at an electrode in the plasma reaction apparatusof FIG. 7.

FIG. 9 is a vertical section view illustrating a plasma reactionapparatus according to a fourth embodiment of the present invention.

FIG. 10 is a schematic view illustrating an apparatus for decreasing NOxaccording to the present invention.

FIG. 11 is a sectional view of a plasma reactor in an apparatus fordecreasing NOx according to a fifth embodiment of the present invention.

FIG. 12 is a sectional view of a flow of a fluid in the plasma reactorof FIG. 11.

BEST MODE Mode for Invention

The present invention will now be described more fully and clearlyhereinafter with reference to the accompanying drawings, in whichpreferred embodiments of the invention are shown.

FIG. 1 is a vertical sectional view illustrating a plasma reactionapparatus according to a first embodiment of the present invention, FIG.2 is a vertical sectional view illustrating a plasma reaction zone whichis expanded by the plasma reaction apparatus of FIG. 1, and FIG. 3 is across sectional view illustrating a structure in which a raw materialinflow pipe is operatively connected to a furnace in the plasma reactionapparatus of FIG. 1.

A plasma reaction apparatus comprises: a furnace, a raw material inflowpipe, and an electrode. The furnace is hollow and includes a dischargeopening, formed at an upper part of the furnace, for discharging aplasma reactant. The raw material inflow pipe for supplying a rawmaterial for a plasma reaction to the inside of the furnace isoperatively connected to a lower part of the furnace, and an intakeopening positioned inside the furnace is formed to be tilted at apredetermined angle to a normal direction of an outer circumferencesurface of the furnace, so that the raw material being supplied isprogressed in the form of a rotating flow inside the furnace. Theelectrode for generating a discharge voltage for the plasma reaction ofthe raw material being supplied to the inside of the furnace ispositioned at the bottom of the furnace and is spaced from an inner wallof the furnace at a predetermined interval. The furnace is characterizedin that the width of a section positioned above the electrode isexpanded. Accordingly, when the raw material being supplied to theinside of the furnace makes the plasma reaction, the furnace expands aplasma reaction zone, thereby forming a broad chamber to temporarilystay the plasma reaction zone.

A plasma reaction method using a plasma reaction apparatus, comprises:supplying a raw material for a plasma reaction to the inside of afurnace by operatively connecting a raw material inflow pipe to thefurnace, wherein the furnace is hollow and includes a discharge opening,formed at an upper part of the furnace, for discharging a plasmareactant, and the raw material inflow pipe includes an intake openingpositioned inside the furnace which is formed to be tilted at apredetermined angle to a normal direction of an outer circumferencesurface of the furnace, so that the raw material being supplied isprogressed in the form of a rotating flow inside the furnace; allowingthe raw material being supplied to make a plasma reaction by a dischargevoltage between an inner wall of the furnace and an electrode, whereinthe electrode is positioned at the bottom of the furnace and spaced fromthe inner wall of the furnace at a predetermined interval; and forming abroad area chamber inside the furnace by expanding the width of asection positioned above the electrode, so that a plasma reaction zoneis expanded and temporarily stayed in the broad area chamber upon theplasma reaction of the raw material being supplied to the inside of thefurnace.

As illustrated in FIGS. 1 through 3, a plasma reaction apparatus 50comprises a furnace 10, an electrode 30 and a raw material inflow pipe20.

The furnace 10 is formed, including a hollow to form a space for aplasma reaction. The specific structure and shape of the furnace will bedescribed later.

The electrode 30 for generating a discharge voltage for the plasmareaction of a raw material being supplied to the inside of the furnace10 is positioned at the bottom of the furnace 10 and spaced from aninner wall of the furnace 10 at a predetermined interval. The electrode30 has the following characteristics in shape.

The electrode 30 includes an upper part in a conical shape and a lowerpart extended in a cylindrical shape. Accordingly, in the electrode 30,the width of an about middle part is relatively expanded compared to theother parts. The extended lower part in the cylindrical shape of theelectrode 30 is relatively narrow in width, compared to the upper partof the electrode 30. The summit of the conical shape and the portionconnecting the conical shape and the cylindrical shape are curvedroundly.

According to the characteristic shape of the electrode 30, a reactionchamber 15 is formed in a section in which the electrode 30 ispositioned inside the furnace 10. In the reaction chamber 15, a plasmareaction is performed by a raw material flowing from a raw materialinflow pipe 20, described later, and a raw material inflow chamber 13 towhich the raw material inflow pipe 20 is operatively connected. That is,the raw material inflow chamber 13 and the reaction chamber 15 aredivided by a middle portion (corresponding to a lower part of theconical shape) in which the width of the electrode 30 is expanded. Theraw material inflow chamber 13 is extendedly formed in a narrowcylindrical shape. Since the interval between the portion in which thewidth of the electrode 30 is expanded and the inner wall of the furnace10 becomes relatively narrow, the raw material being flowed into thefurnace does not immediately progress to the reaction chamber 15.Rather, after the raw material is temporarily stayed in the raw materialinflow chamber 13 of a relatively large volume and is sufficientlymixed, the raw material is progressed to the reaction chamber 15. Thatis, the above-described shape of the electrode 30 enables the section inwhich the electrode 30 is formed inside the furnace 10 to divide the rawmaterial inflow chamber 13 and the reaction chamber 15, enables the rawmaterial inflow chamber 13 to have a sufficient volume, and enables theraw material supplied from the raw material inflow chamber 13 to berestrictively progressed into the reaction chamber 15 so that the rawmaterial is sufficiently mixed.

The raw material inflow pipe 20 is operatively connected to a lower partof the furnace 10, to allow the raw material for the plasma reaction toflow into the raw material inflow chamber 13 inside the furnace 10. Thenumber of the raw material inflow pipes is not limited. An intakeopening (hereinafter, referred to as a inflow hole) positioned in thefurnace connected to the raw material inflow pipe 20 is formed to betilted to a wall surface of the furnace 10, that is, the inflow hole 21has a swirl shape. The inflow hole 21 allows the raw material to form arotating flow and progress in the furnace. This enables the raw materialto form the rotating flow and progress in the reaction chamber 15.Accordingly, the raw material rotates in a circumference direction andmoves upwardly rather than it directly moves upwardly along a lengthdirection of the furnace 10. The rotating progress of the raw materialenhances the efficiency on the plasma reaction to the same volume.

According to the first embodiment of the present invention, thestructure and shape of the furnace 10 is desirably presented as follows:

The furnace 10 is formed including a hollow. The appearance of thefurnace 10 has nearly a cylindrical shape. As described above, the lowerpart of the furnace 10 is connected to the raw material inflow pipe 20.The upper part of the furnace 10 is opened to form a discharge opening11. The discharge opening 11 is formed to discharge a plasma reactant.The upper part of the furnace 10 is expanded in width, thereby forming abroad area chamber 17 at the upper part in the furnace 10. The broadarea chamber 17 may be positioned above the top tip of the electrode 30.That is, the furnace 10 has the wider section positioned above theelectrode 30. According to the above description, the raw materialinflow chamber 13, the reaction chamber 15 and the broad area chamber 17are sequentially formed from the lower position to the upper position inthe furnace 10. Since the broad area chamber 17 is expanded than thereaction chamber 15, when the raw material makes the plasma reaction inthe reaction chamber 15, a plasma reaction zone is expanded through thebroad area chamber 17 and is temporarily stayed. Then, the time forwhich a plasma reaction product is stayed is increased, thereby makingit favorable for an additional high temperature reaction and resultingin the acting effect of excluding the discontinuity of plasma formation.The point to divide the broad area chamber 17 and the reaction chamber15 in the furnace 10, that is, the start point at which the inside ofthe furnace 110 is expanded, may be formed in a pointed end 19 ratherthan a round curve. For this purpose, the section positioned above theelectrode 30 in the furnace 10 is formed and expanded in a right-angledshape. According to the structure in which the furnace 10 is expanded inthe right-angle shape, the horizontal expansion of the plasma reactionzone in the broad area chamber 17 is increased, and the plasma reactionis continuously performed since the pointed end 19 with plasma isrotated.

When staying plasma is formed by the broad area chamber 17, rotatingplasma is formed through the pointed end 19 formed between the reactionchamber 15 and the broad area chamber 17 from the top tip of theelectrode 30. The distance from the pointed end 19 formed between thereaction chamber 15 and the broad area chamber 17 to the top tip of theelectrode 30 is a factor to decide a thermal characteristic of theplasma being formed.

An auxiliary raw material inflow pipe 25 for supplying an additional rawmaterial to the broad area chamber 17 is operatively connected to thefurnace 10, thereby enabling an additional reaction by the added rawmaterial in the broad area chamber 17.

When the diameter of the discharge opening 11 is formed to be smallerthan the diameter of the broad area chamber 17 in the furnace 10, theplasma reactant may more stay or stop in the broad area chamber 17. Inthe first embodiment, the upper part of the furnace is expanded once butit may be expanded in a number of steps and/or in a number of times.Such modification is within the scope of the present invention.

In the shape of the reactor, when the expanded region is formed, in theform of a step, at the rear of the reactor, the plasma being formed onconditions does not leave and is attached to the tip of the electrodewhile it continuously discharges and rotates. On the conditions thathydrocarbon fuel is partially oxidized, the staying plasma becomespersistent due to the high temperature and the concentration of a matterwith high reactivity (for example, electrons and ions), therebyimproving the performance in resolving the gas and in reforming thefuel.

FIG. 4 is a vertical sectional view illustrating a plasma reactionapparatus according to a second embodiment of the present invention,FIG. 5 is a vertical sectional view illustrating a plasma reaction zonewhich is stayed by the plasma reaction apparatus of FIG. 4, and FIG. 6is a cross sectional view illustrating the plasma reaction apparatus ofFIG. 4.

The second embodiment of the present invention will be described, indetail, as follows:

A plasma reaction method of resolving a persistent gas comprises:flowing a persistent gas, hydrocarbon fuel and an oxidizer into afurnace through a raw material inflow pipe operatively connected to thefurnace, so that when the persistent gas makes a plasma reaction by adischarge voltage generated between an electrode installed in thefurnace and an inner wall of the furnace, a plasma region is in a highertemperature state by heat generated by an oxidation reaction of the fueland is lower in density; making a continuous plasma reaction by allowinga plasma reaction zone generated upon the plasma reaction to stay in anexpanded section formed as the width of a section positioned above theelectrode in the furnace is expanded, forming a step at a right angle ina length direction of the furnace; and forming a number of inflow holeson a wall surface of the furnace and so as to be tilted at apredetermined angle to a normal direction of the inner wall of thefurnace, the inflow holes for operatively connecting the raw materialinflow pipe and the inside of the furnace.

The present invention having the above-described characteristics will bemore clearly described with reference to a preferred embodiment thereof.

Before the preferred embodiment of the present invention will bedescribed, it is noted that the present invention relates to a method ofresolving a persistent gas by a plasma reaction and the persistent gasmay be any one of typical gases causing the global warming, such as CF₄,C2F₆, SF₆ and NF or a mixture thereof but any other persistent gases arewithin the scope of the present invention.

The preferred embodiment of the present invention will be described withreference to the accompanying drawings.

According to the second embodiment of the present invention, thedesirable constitution and structure of a plasma reaction apparatus 50for a plasma reaction of a persistent gas is presented.

A raw material inflow pipe 20 for allowing the inflow of a persistentgas, hydrocarbon fuel and an oxidizer which are subject to a plasmareaction is connected to a furnace 10 including a hollow. An electrode30 for generating a discharge voltage for the plasma reaction betweenthe electrode 30 and the inner wall of the furnace 10 is installed inthe furnace 10.

In the structure of operatively connecting the raw material inflow pipe20 to the furnace 10, a number of inflow holes 21 are formed on a wallsurface of the furnace 10, for the operative connection between the rawmaterial inflow pipe 20 and the inside of the furnace 10. The inflowholes 21 are formed to be tilted at a predetermined angle to a normaldirection of the inner wall of the furnace 10. A space 21 a in which thegases (the persistent gas, the fuel and the oxidizer) to flow into thefurnace 10 are temporarily stayed is formed between the inflow holes 21of the furnace 10 and the raw material inflow pipe 10.

According to the foregoing, the gases flowing through the raw materialinflow pipe 20 temporarily stay in the space 21 a and then uniformlyspread inside of the furnace 10 through the number of inflow holes 21.As the inflow holes 21 are formed to be tilted, the gases being flowedinto form a rotating flow and progress inside the furnace 10.

As described above, a broad area chamber 17 for staying a plasmareaction zone generated upon the plasma reaction is formed inside thefurnace 10. The broad area chamber 17 is formed as the width of asection positioned above the electrode 30 is expanded in the furnace 10.

The section positioned above the electrode 30 in the furnace 10 isexpanded forming a step at a right angle in a length direction of thefurnace 10. Accordingly, a pointed end 19 is formed at a start pointwhen the expanded section is formed in the furnace 10.

In the plasma reaction apparatus 50 with the above-described structure,the persistent gas, the hydrocarbon fuel and the oxidizer are firstflowed into the furnace through the raw material inflow pipe 20 on thepartial oxidization conditions. In the second embodiment, CH₄ is used asthe fuel and O₂ is used as the oxidizer.

Any other combustible gases may be used as the fuel and any other gasesto induce an oxidation reaction of the fuel may be used as the oxidizer.

The persistent gas, the fuel and the oxidizer may be sequentially orsimultaneously flowed into the furnace 10.

That is, after the fuel and the oxidizer are flowed into the furnace 10,the persistent gas may be flowed into the furnace 10. Or the fuel, theoxidizer and the persistent gas may be flowed into the furnace 10simultaneously.

As described above, when the persistent gas, the fuel and the oxidizerare flowed into the furnace 10, the persistent gas makes the plasmareaction by the discharge voltage generated between the electrode 30being installed inside the furnace 10 and the inner wall of the furnace10. Then, the plasma region is in a higher temperature state by the heatgenerated by the oxidation reaction of the fuel, thereby lowering thedensity of the plasma region. In the expanded plasma reaction zone, thedensity of electrons is increased since an electric current becomeshigher, and the dissolution of the persistent gas is speeded up asradicals with high reactivity generated during the collision with theelectrons and the oxidation reaction are rapidly increased. In addition,the radicals and ions with the high reactivity are generated during theoxidation reaction of the fuel, thereby improving the reactivity.

Consequently, the fuel and the oxidizer increase the efficiency on theplasma reaction of the persistent gas, thereby enhancing theresolvability of the persistent gas. Furthermore, the broad area chamber17 formed inside the furnace 10 enables the continuous plasma reactionof the persistent gas.

According to the second embodiment of the present invention, the broadarea chamber 17 formed in the furnace 10 expands the plasma reactionzone generated by the plasma reaction of the persistent gas inside thefurnace 10, and the pointed end 19 formed at the start point of thebroad area chamber 17 holds the plasma reaction zone, so that the plasmareaction zone is stayed in the broad area chamber 17 rather than it isdirectly discharged through a discharge opening 37 of the furnace 10.Furthermore, since the persistent gas flowed into the furnace 10 formsthe rotating flow inside the furnace 10 as described above, the plasmareaction zone is likely to be more attached to the pointed end 19 of thebroad area chamber 17.

As described above, when the plasma reaction zone is stayed inside thefurnace 10, the persistent gas which is subsequently flowed into thefurnace 10 continuously makes the plasma reaction by the plasma reactionzone being once generated. Consequently, the continuous plasma reactionis made, thereby preventing a loss on reaction caused by thediscontinuous plasma reaction made by the plasma reaction zone which isperiodically and repeatedly generated.

FIG. 7 is a vertical section view illustrating a plasma reactionapparatus according to a third embodiment of the present invention, andFIG. 8 is a cross sectional view illustrating a structure in which aninflow path is formed at an electrode in the plasma reaction apparatusof FIG. 7. The third embodiment of the present invention will bedescribed as follows:

A plasma reaction apparatus according to the third embodiment of thepresent invention comprises: a furnace; an electrode and a heatabsorption tank. The furnace includes a lower part side to which a rawmaterial inflow pipe for supplying a raw material for a plasma reactionis connected, an upper part at which a discharge opening for discharginga plasma reactant is formed, and a hollow in which a section positionedabove an electrode is expanded in width, thereby forming a broad areachamber for temporarily staying a plasma reaction zone when the rawmaterial being supplied to the inside of the furnace makes the plasmareaction. The electrode is protruded towards the inside of the furnace,for generating a discharge voltage for the plasma reaction of the rawmaterial being supplied. The electrode is put into and connected to thebottom of the furnace and spaced from the wall surface of the furnace ata predetermined interval. The heat absorption tank is operativelyconnected to each of a liquefied raw material inflow pipe for allowing aliquefied raw material to flow into a chamber formed in the furnace anda liquefied raw material supply pipe with one side connected to thefurnace, for supplying the liquefied raw material flowed into thechamber to the inside of the furnace. The heat absorption tank ispositioned in the broad area chamber, so that the liquefied raw materialflowed into the chamber absorbs heat in the chamber.

The plasma reaction apparatus with the above-described characteristicswill be more clearly described with reference to a preferred embodimentthereof.

The plasma reaction apparatus according to the preferred embodiment ofthe present invention will be described, in detail, with reference tothe accompanying drawings.

Before the plasma reaction apparatus according to the third embodimentis described, it is noted that the present invention relates to anapparatus for performing a reforming reaction of a liquefied or gaseousraw material by a plasma reaction or an apparatus for disposing of a rawmaterial of various harmful matters, such as, waste matter andautomobile exhaust gas, by a plasma reaction, and that the raw materialmentioned below includes chemical compositions and various harmfulmatters which are harmful to environment.

As illustrated in FIGS. 7 and 8, the plasma reaction apparatus 50according to the third embodiment largely comprises a furnace 10, anelectrode 30 and a heat absorption tank 93.

The furnace 10 includes a hollow for providing a space for a plasmareaction and has an about cylindrical shape. The furnace 10 includes alower part side to which a raw material inflow pipe 91 for receiving araw material for the plasma reaction is connected, and an upper part atwhich a discharge opening 92 for discharge a plasma reactant is formed.

The characteristic structure and shape of the furnace 10 will be morespecifically described as follows:

In the upper part of the furnace 10, a broad area chamber 17 is formedas the width of a section positioned above the electrode 30 is expanded.When the broad area chamber 17 is formed inside the furnace 10, a plasmareaction zone, which is formed by the plasma reaction in the section inwhich the electrode 30 is positioned in the furnace 10, is expandedthrough the broad area chamber 17 and is temporarily stayed there.Accordingly, the time for which a plasma reaction product is stayed isincreased, thereby making it favorable to an additional reaction at ahigh temperature and resulting in the acting effect of excluding thediscontinuity of plasma formation. Since the plasma reaction zone isstayed, a region of a higher temperature is formed in the broad areachamber 17. This is favorable for a liquefied raw material to absorbheat in the heat absorption tank 93, which will be described later. Theupper part of the furnace 10 is bent, forming a step at a right angle.The discharge opening 92 formed at the top in the upper part of thefurnace 10 is not positioned at a vertically extending line of the broadarea chamber 17. According to the above-described structure, the plasmareaction zone is more stayed in the broad area chamber 17. As a derivingacting effect, a more reliable region of a high temperature is formed inthe broad area chamber 17.

The electrode 30 is protruded towards the inside of the furnace 10 andgenerates a discharge voltage for the plasma reaction of the rawmaterial being supplied to the inside of the furnace 10. The electrode30 is spaced from the wall surface of the furnace 10 at a predeterminedinterval and is put through the bottom of the furnace 10 to be connectedthereto. The electrode 30 is connected to an outside power supply (notshown) for generating the voltage. The electrode 30 has the followingcharacteristics in shape:

An upper part of the electrode 30 has a conical shape and a lower partthereof has an extended cylindrical shape. Accordingly, in the electrode30, the width of an about middle part corresponding to the bottom of theconical shape is relatively expanded, compared to the other parts. Thelower part being extendedly formed in the cylindrical shape is relativenarrow in width, compared to the upper part of the electrode 30. Thesummit of the conical shape and the portion connecting the conical shapeand the cylindrical shape are roundly curved in the electrode 30.According to the above-described structure, the interval between theelectrode 30 and the inner wall of the furnace 10 is different dependingon a height direction of the electrode 30. That is, the interval betweenthe electrode 30 and the inner wall of the furnace 10 is narrow aroundthe middle part of the electrode 30, and the interval maintains arelatively broad space from the inner wall of the furnace 10 in theupper part and lower part around the middle part of the electrode 30.Accordingly, when the raw material is flowed into a section positionedbelow the middle part of the electrode 30 in the furnace 10, since theinterval between the middle part of the electrode 30 and the inner wallof the furnace 10 is narrow, the raw material is temporarily stayed andis sufficiently mixed at the lower part of the electrode 30 and isprogressed rather than it is directly progressed to the upper part ofthe electrode 30.

Further, the electrode includes a structure for additionally supplying aliquefied raw material, and this will be described below:

A raw material inflow chamber 35 with a predetermined space is formedinside the electrode 30. An auxiliary liquefied raw material supply pipe31 for allowing a liquefied raw material to flow into the raw materialinflow chamber 35 is connected to the bottom of the electrode 30. Aninflow path 94 for supplying the raw material in the raw material inflowchamber 35 to the inside of the furnace 10 (preferably, to the lowerpart of the electrode) is formed through the inner wall of the electrode30. Accordingly, the liquefied raw material is additionally supplied tothe inside of the furnace 10, without connecting any additional pipes tothe furnace 10.

An auxiliary gas supply pipe 33 is operatively connected to theauxiliary liquefied raw material supply pipe 31. Accordingly, theliquefied raw material and the gas for separating the liquefied rawmaterial in fine particles are flowed into the raw material inflowchamber 35, thereby enabling the liquefied raw material to besufficiently dispersed inside the raw material inflow chamber 35 and thefurnace 10.

The heat absorption tank 93 is installed in the furnace 10, to bepositioned in the broad area chamber 17. The heat absorption tank 93 hasa sphere shape in appearance. A chamber 55 with a predetermined space isformed inside the heat absorption tank 93. The heat absorption tank 93is operatively connected to a liquefied raw material inflow pipe 51 forallowing the liquefied raw material to flow into the chamber 55. Theheat absorption tank 93 is operatively connected to a liquefied rawmaterial supply pipe 57 for supplying the liquefied raw material whichflows into the chamber 55 to the inside of the furnace 10. That is, theliquefied raw material supply pipe 57 has one side being operativelyconnected to the furnace 10 and the other side being operativelyconnected to the heat absorption tank 93, thereby allowing the liquefiedraw material in the chamber 55 to be supplied to the inside of thefurnace 10. The one side of the liquefied raw material supply pipe 57may be operatively connected to the lower part of the furnace 10,preferably, to the section positioned below the middle part of theelectrode 30, and may be wound around the outer circumference surface ofthe furnace 10 to sufficiently absorb the heat from the furnace 10.Preferably, the liquefied raw material inflow pipe 51 may be operativelyconnected to the upper part of the heat absorption tank 93 and may beperpendicular to the bottom of the furnace 10. This structure allows theliquefied raw material to be vertically supplied from the upper part tothe lower part to the chamber 55 of the heat absorption tank 93.Accordingly, the liquefied raw material supplied to the chamber 55 moredirectly and more easily reaches the bottom surface of the heatabsorption tank 93 in contact with a high temperature plasma reactionzone inside the furnace 10, thereby enhancing the efficiency on heatabsorption. The liquefied raw material inflow pipe 51 may be horizontalto the bottom of the furnace 10 and may be operatively connected to aside of the heat absorption tank 93. This structure is favorable when anumber of liquefied raw material inflow pipes 51 are operativelyconnected to the heat absorption tank 93. For example, when a pluralityor a number of liquefied raw material inflow pipes 51 are operativelyconnected to the heat absorption tank 93 to face each other, theliquefied raw material supplied to the chamber 55 of the heat absorptiontank 93 through each liquefied raw material inflow pipe 51 is moreeffectively mixed. The third embodiment illustrates a single liquefiedraw material inflow pipe 51 which is operatively connected to the upperpart of the heat absorption tank 93 and which is perpendicular to thebottom of the furnace 10. Since the structure in which the liquefied rawmaterial inflow pipe 51 is operatively connected to the heat absorptiontank and is horizontal to the bottom of the furnace is considered to beeasily applicable and carried out by those skilled in the art, based onthe third embodiment of the present invention, it is not presented indrawings. The third embodiment illustrates that the liquefied rawmaterial inflow pipe 51 is operatively connected to the heat absorptiontank 93 in order to supply the liquefied raw material to the heatabsorption tank 93. However, the liquefied raw material may be injectedinto the chamber 55, using an injecting device (not shown) beingoperatively connected to the heat absorption tank 93. This modificationis obviously within the scope of the present invention.

A gas supply pipe 53 is operatively connected to the liquefied rawmaterial inflow pipe 51, thereby allowing the liquefied raw material andthe gas for separating the liquefied raw material in fine particles toflow into the chamber 55. When the liquefied raw material and the gas(for separating the liquefied raw material in fine particles) flow intothe chamber through the gas supply pipe 53, the liquefied raw materialis more effectively spread or activated.

A heater 59 as a heating unit for forcibly heating the liquefied rawmaterial flowing into the chamber 55 is installed in the heat absorptiontank 93. At a start point when a high temperature environment isincompletely formed in the broad area chamber 17 of the furnace 10, thatis, at the beginning of operating the plasma reaction apparatus 50, theheater 59 forcibly heats or vaporizes the liquefied raw material flowinginto the chamber 55.

The heater 59 is electrically connected to an outside power source (notshown). The heater 59 is positioned in the heat absorption tank 93 andprotrudes in the chamber 55 of the heat absorption tank 93. Although theheater 59 may be installed inside a wall frame of the heat absorptiontank 93, it is installed to protrude in the chamber 55 so that the rawmaterial directly contacts with the surface of the heater 59 in thechamber 55 and is effectively vaporized. When the heater 59 isinstalled, components and portions for the electrical connection need tobe coated with an insulating material in order to prevent an electricshort inside the furnace 10.

According to the heat absorption tank 93 and its relevant constitutionand structure as described above, the liquefied raw material flowingthrough the liquefied raw material inflow pipe absorbs heat in thechamber 55 and is dispersed or activated to be supplied to the inside ofthe furnace 10 through the liquefied raw material supply pipe 57.Accordingly, the liquefied raw material being supplied is more easilymixed with other raw materials (for example, the gaseous raw material)and is spread on the entire surface of the electrode, thereby enablingthe plasma reaction to be more effectively performed.

FIG. 9 is a vertical section view illustrating a plasma reactionapparatus according to a fourth embodiment of the present invention. Inthe plasma reaction apparatus according to the fourth embodiment, amixing tank 70 is formed at an outer wall of the furnace 10, and a rawmaterial inflow pipe 91 and a liquefied raw material supply pipe 57 areoperatively connected to the furnace 10 by the mixing tank 70. A mixingchamber 75 of a predetermined volume is formed inside the mixing tank70. Accordingly, the raw materials which respectively progress from theraw material inflow pipe 91 and the liquefied raw material supply pipe57 are mixed in the mixing chamber 75 formed inside the mixing tank 70and are supplied to the inside of the furnace 10. That is, the mixingtank 70 is operatively connected to the raw material inflow pipe 91, theliquefied raw material supply pipe 57 and the furnace 10. Theconstitution of the mixing tank 70 as described above improves themixability of the raw materials which are supplied through the rawmaterial inflow pipe 91 and the liquefied raw material supply pipe 57.An additional heating unit (not shown) may be installed in the mixingtank 70 if necessary.

FIG. 10 is a schematic view illustrating an apparatus for decreasing NOxaccording to the present invention; FIG. 11 is a sectional view of aplasma reactor in an apparatus for decreasing NOx, according to a fifthembodiment of the present invention, and FIG. 12 is a sectional view ofa flow of a fluid in the plasma reactor of FIG. 11. An apparatus fordecreasing NOx moves an exhaust gas, which is released from an engineusing hydrocarbon fuel supplied from a storage, to an occlusioncatalyst; adsorbing NOx of the exhaust gas to the occlusion catalyst,and then reducing NOx to be removed. The apparatus for decreasing NOxcomprises a plasma reactor which is connected to a path through whichthe exhaust gas is moved from the engine to the occlusion catalyst andwhich reforms the hydrocarbon fuel partially supplied from the storageto a reducing ambient gas of high temperature from the plasma reactor bya plasma reaction.

The apparatus for decreasing NOx comprises a body; an electrode; and aliquefied fuel injection unit. The body includes a furnace and a base.The furnace includes a discharge opening and a hollow. The dischargeopening is formed at one side of the furnace. The hollow includes a heatabsorption path formed in a wall frame forming the thickness of thefurnace, and the heat absorption path allows a gas flowing from a gasinflow opening to move and to absorb heat. The base forms the bottom ofthe furnace and includes a mixing chamber. The mixing chamber isoperatively connected to the heat absorption path and the inside of thefurnace through an inflow hole formed at the furnace. The electrode isspaced from an inner wall of the furnace, fixed to the base andprotrudes in the furnace, in order to form a discharge voltage for aplasma reaction in the furnace. The electrode includes a heat absorptionchamber which is operatively connected to the mixing chamber. Liquefiedfuel flows into the heat absorption chamber. The liquefied fuelinjection unit is fixed to the body and supplies the liquefied fuel tothe heat absorption chamber of the electrode.

The apparatus for decreasing NOx with the above-describedcharacteristics will be more clearly described with reference to apreferred embodiment thereof.

The apparatus for decreasing NOx according to the preferred embodimentof the present invention will be described, in detail, with reference tothe accompanying drawings.

As illustrated in FIGS. 10 through 12, an apparatus 200 for decreasingNOx according to the present invention moves an exhaust gas, which isreleased from an engine 220 using hydrocarbon fuel supplied from a fueltank 21 which is a storage storing the hydrocarbon fuel, to an occlusioncatalyst 30 and removes NOx of the exhaust gas.

The occlusion catalyst 30 is called a lean NOx trap (LNT) catalyst. WhenNOx of the exhaust gas being moved is adsorbed, the occlusion catalyst30 reduces NOx to be removed. Since the detailed constitution and actionof the occlusion catalyst 30 are well known, no description thereof willbe presented.

The apparatus 200 for decreasing NOx comprises a plasma reactor 50. WhenNOx is reduced by the occlusion catalyst 30, the plasma reactor 50injects a reducing ambient gas of high temperature to be supplied to theocclusion catalyst 30. The plasma reactor 50 is connected to the fueltank 210. The plasma reactor 50 acts as a reformer for reforming thehydrocarbon fuel, which is partially supplied from the fuel tank 210 tothe plasma reactor 50, to the reducing ambient gas of high temperatureby a plasma reaction.

In the plasma reactor 50, a discharge opening 62 may be installedtowards the occlusion catalyst 30 so that the reducing ambient gasreformed by the plasma reaction is discharged from the plasma reactor 50and is injected to the occlusion catalyst 30. The discharge opening 62of the plasma reactor 50 may be simply operatively connected to amovement pipe 40 through which the exhaust gas is moved, as shown.

The characteristic constitution of the plasma reactor for generating thereducing ambient gas of high temperature from the hydrocarbon fuel willbe described below:

The plasma reactor 50, which is used as the reformer in the apparatus200 for decreasing NOx according to the present invention, largelycomprises: a body 60, an electrode 70 and a liquefied fuel injectionunit.

The body 60 includes a furnace 61 and a base 65.

The furnace 61 includes a hollow and has an about cylindrical shape. Adischarge opening 62 is formed at one side of the furnace 51 anddischarges a reacted matter after the plasma reaction. A gas inflowopening 63 is formed in the furnace 61 and allows a gas to flow into theinside of the furnace 61. A heat absorption path 64 is formed inside awall frame forming the thickness of the furnace 61 and allows the gasflowing from the gas inflow opening 63 to move along a circumferencedirection and to absorb heat. The heat absorption path 64 is formed inan about coil shape, along the circumference direction of the furnace61.

The base 65 forms the bottom of the furnace 61. A mixing chamber 67 of apredetermined volume is formed in the base 65. The mixing chamber 67 isoperatively connected to the heat absorption path 64 formed in the wallframe of the furnace 61 and is simultaneously operatively connected tothe inside of the furnace 61 through an inflow hole 68 formed at thefurnace 61. Preferably, the inflow hole 68 may be formed to be tilted ata predetermined angle to a normal of an inner wall of the furnace 61,that is, in a swirl structure.

The furnace 61 and the base 65 may be formed in one body or may beseparately formed to be connected to each other. The base 65 needs toinclude an insulator (not shown), such as ceramic, to prevent theapplication of an electric current between a lower part of the electrode70, which will be described below, and the furnace 61.

The electrode 70 is to generate a discharge voltage for the plasmareaction in the furnace 61. For this purpose, the electrode 70 is spacedfrom the inner wall of the furnace 61 at a predetermined interval and isfixed to the base 65 to protrude in the furnace 61. The electrode has anabout conical shape. A heat absorption chamber 75 is formed in theelectrode. The heat absorption chamber 75 is operatively connected tothe mixing chamber 67. Liquefied fuel being supplied from the liquefiedfuel injection unit flows into and temporarily stays in the heatabsorption chamber 75.

The liquefied fuel injection unit is connected to the fuel tank 210 andsupplies the liquefied fuel stored in the fuel tank 210 to the heatabsorption chamber 75 of the electrode 70. The liquefied fuel injectionunit is fixed to the body 60. A liquefied fuel injection device 80 or aninjector (not shown) may be used as the liquefied fuel injection unit.The liquefied fuel injection device 80 injects the liquefied fuel to theabsorption chamber 75 by a movement force of a gas supplied from thefuel tank 210, together with the liquefied fuel. The injector (notshown) directly injects the liquefied fuel to the heat absorptionchamber 75 of the electrode 70.

FIGS. 11 and 12 illustrates the liquefied fuel injection device 80 usedas the liquefied fuel injection unit.

That is, the liquefied fuel injection device 80 includes the liquefiedfuel supply pipe 81, which is operatively connected to the fuel tank 210and supplies the liquefied fuel, and a gas supply pipe 82, which isoperatively connected to an outside gas supply source, independentlyfrom the liquefied fuel supply pipe 81, and supplies a gas, therebyallowing the inflow of the liquefied fuel and the gas simultaneously.The side from which the liquefied fuel and gas are injected face towardsthe heat absorption chamber 75 of the electrode.

An operational example of the apparatus for decreasing NOx according tothe present invention will be described below:

An exhaust gas, which is generated according to the operation of anengine 220, is moved to an occlusion catalyst 30 through a movement pipe40. The movement pipe 40 is operatively connected to the side of adischarge opening 62 of a plasma reactor 50, so that a reducing ambientgas of high temperature generated from the plasma reactor 50 is moved tothe occlusion catalyst 30 and speeds up a reducing action of NOx in theocclusion catalyst 30.

The action of the plasma reactor 50 will be described in more detail.The plasma reactor 50 receives hydrocarbon fuel supplied from a fueltank 210 through a liquefied fuel injection device 80 and simultaneouslyallows an inflow of air including O₂, which acts as an oxidizer neededupon a reforming reaction of the liquefied fuel (hydrocarbon fuel) beingsupplied, through a gas inflow opening 63. When temperature sufficientlyrises and is activated, the air is moved to a mixing chamber 67 througha heat absorption path 64. When the liquefied fuel, which is moved to aheat absorption chamber 75 of an electrode 70 through the liquefied fuelinjection device 80, absorbs heat in the heat absorption chamber 75 andis vaporized and activated, the liquefied fuel is moved to the mixingchamber 67 to be mixed with the air in the mixing chamber 67 and thenflows into a furnace 61 through an inflow hole 68.

In accordance with the forgoing, it is noted that after the air and theliquefied fuel being supplied are sufficiently mixed in the mixingchamber 67, they flow into the furnace 61. Furthermore, since theliquefied fuel is directly injected from the heat absorption chamber 75and the liquefied fuel is prevented from directly contacting with theouter surface of the electrode 70, the wetting and coking phenomena ofthe liquefied fuel are prevented. Furthermore, since the liquefied fuelabsorbing heat in the heat absorption chamber 75 is immediately mixedwith the air in the mixing chamber 67, the liquefied fuel is basicallyprevented from being liquefied during its movement.

The mixed fuel of the liquefied fuel and the air which are supplied tothe inside of the furnace through the inflow hole 68 makes a plasmareaction with relatively high efficiency, compared to a volume, becauseof the characteristic structures of the inflow hole 68 and the electrode70. That is, in accordance with the present invention, since theelectrode 70 has a conical shape and the inflow hole 68 is formed in theswirl structure, the mixed fuel flowing into the furnace through theinflow hole 68 continuously makes the plasma reaction, along thecircumference direction of the electrode 70.

In the plasma reactor 50 as described above, the reducing ambient gas,which is generated by reforming the liquefied fuel and the air as theoxidizer being first supplied, may be hydrocarbon (HC), carbon monoxide(CO) or hydrogen (H2). On the conditions that the ambient gas issupplied, NOx is reduced to a nitrogen (N2) gas.

Furthermore, when the plasma reactor 50, which is illustrated in FIG. 10as the schematic view of the apparatus for decreasing NOx according tothe present invention, uses the constitution of the plasma reactionapparatus 50 described with reference to the first through fourthembodiments, the same effects as the fifth embodiment are obtained.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A plasma reactor comprising: a body including a furnace being hollowand a base forming a bottom of the furnace, wherein a discharge openingis formed at one side of the furnace, a heat absorption path is formedinside a wall frame, with a thickness, of the furnace and allows a gasflowing from a gas inflow opening to move and absorb heat, and a mixingchamber, which is operatively connected to the heat absorption path andsimultaneously to the inside of the furnace through an inflow holeformed at the furnace, is formed inside the base; an electrode spacedfrom an inner wall of the furnace, fixed to the base and protruded inthe furnace, to generate a discharge voltage for a plasma reactioninside the furnace, wherein a heat absorption chamber which isoperatively connected to the mixing chamber is formed inside theelectrode, and liquefied fuel is allowed to flow into the heatabsorption chamber; and a liquefied fuel injection unit fixed to thebody, to supply the liquefied fuel to the heat absorption chamber of theelectrode.
 2. The plasma reactor of claim 1, wherein the electrode has aconical shape, and the inflow hole is formed to be tilted at apredetermined angle to a normal of the inner wall of the furnace so thatmixed fuel, resulted from the mixture of a gas and the liquefied fuel inthe mixing chamber, forms a rotating flow to flow into the furnace andprogresses, along an outer circumference surface of the electrode. 3.The plasma reactor of claim 1, wherein the liquefied fuel injection unitis a liquefied fuel injection device which injects the liquefied fuel tothe heat absorption chamber by a movement force of the gas beingsupplied, together with the liquefied fuel.
 4. The plasma reactor ofclaim 1, wherein the liquefied fuel injection unit is an injector whichdirectly injects the liquefied fuel to the heat absorption chamber ofthe electrode.
 5. An apparatus for decreasing NOx by an occlusioncatalyst using a plasma reactor, in which, after an exhaust gasdischarged from an engine using hydrocarbon fuel supplied from a storageis moved to an occlusion catalyst and NOx of the exhaust gas is adsorbedto the occlusion catalyst, NOx is reduced to be removed, comprising: aplasma reactor being connected to a movement path through which theexhaust gas is moved from the engine to the occlusion catalyst, theplasma reactor for reforming the hydrocarbon fuel partially suppliedfrom the storage to a reducing ambient gas of high temperature by aplasma reaction, so that the reducing ambient gas generated from theplasma reactor is supplied upon the reduction of NOx in the occlusioncatalyst.
 6. The apparatus for decreasing NOx of claim 5, wherein theplasma reactor is formed by using a plasma reaction apparatus, theplasma reaction apparatus comprising: a furnace which is hollow andincludes a discharge opening formed at an upper position of the furnace,the discharge opening for discharging a plasma reactant; a raw materialinflow pipe which is operatively connected to a lower part of thefurnace, so that a raw material for a plasma reaction is supplied to theinside of the furnace, and which includes an intake opening positionedin the furnace and formed to be tilted at a predetermined angle to anormal direction of an outer circumference surface of the furnace, sothat the raw material being supplied forms a rotating flow andprogresses inside the furnace; and an electrode which is put through abottom of the furnace and is spaced from an inner wall of the furnace ata predetermined interval, so that a discharge voltage is generated forthe plasma reaction for the raw material being supplied to the inside ofthe furnace; wherein the furnace includes a section positioned above theelectrode and expanded in width, so that a broad area chamber is formedto expand a plasma reaction zone to be temporarily stayed in the broadarea chamber when the raw material being supplied to the furnace makesthe plasma reaction.
 7. The plasma reaction apparatus of claim 6,wherein the section positioned above the electrode in the furnace isexpanded to form a step at a right angle to form a pointed end at astart point when the inside of the furnace is expanded.
 8. The plasmareaction apparatus of claim 6, wherein the electrode has an upper partin a conical shape and a lower part in an extended cylindrical shape, sothat a width of a middle part of the electrode is expanded.
 9. Theplasma reaction apparatus of claim 6, wherein the furnace is operativelyconnected to an auxiliary raw material inflow pipe, so that anadditional raw material is supplied to the broad area chamber to bereacted.